1. Field of the Invention
The present invention relates to semiconductor packages and methods of manufacturing semiconductor packages and, more particularly, relates to a ball grid array (BGA) package and a method of manufacturing such a package.
2. Description of the Related Art
Ball grid array (BGA) packages are used for mounting of and making electrical connections to semiconductor chips. FIG. 1 is a cross-sectional view of a conventional BGA package 30. As illustrated in FIG. 1, the BGA package 30 includes a semiconductor chip 31 mounted on a top surface of a substrate 33 via an adhesive 32. The exposed top surfaces of the semiconductor chip 31 and the substrate 33 are encapsulated and protected by a mold resin 36. Solder balls 35 formed on a bottom surface of the substrate 33 are attached to conductive ball lands 34a and 34b. 
In the BGA package 30, the surfaces of the conductive ball lands 34a and 34b are in direct contact with the adhesive 32 or the mold resin 36 respectively. Because both the adhesive 32 and the mold resin 36 typically have a high modulus of elasticity, when the BGA package 30 is mounted on a printed circuit board (PCB) made of, for example, an epoxy-glass material, the solder balls 35 are subjected to shearing stresses applied to the joints resulting from differences in the coefficient of thermal expansion between the PCB and the solder balls 35. Overtime, these shearing stresses tend to degrade the solder joint reliability (SJR) of the resulting device.
Further, as shown in FIG. 1, the conductive ball lands 34b in contact with the mold resin 36 may be bent downwardly or otherwise deformed as a result of the high pressure applied as the mold resin 36 is cast. If the conductive ball lands 34b are deformed, the SJR of the resulting device will typically be degraded further.